In this handout photo provided by Disney Parks, Super Bowl XLVII MVP Joe Flacco poses with Mickey and Minnie Mouse at the Magic Kingdom at Walt Disney World Resort February 4, 2013 in Lake Buena Vista, Florida. Flacco led his Baltimore Ravens to a 34-31 win over the San Francisco 49ers last...

In this handout photo provided by Disney Parks, Super Bowl XLVII MVP Joe Flacco poses with Mickey and Minnie Mouse at the Magic Kingdom at Walt Disney World Resort February 4, 2013 in Lake Buena Vista, Florida. Flacco led his Baltimore Ravens to a 34-31 win over the San Francisco 49ers last... (Matt Stroshane/Disney Parks Photo via Getty Images)

"It’s been good," quarterback Joe Flacco said. "Matt was a great center, and I think Gino has done a great job last year of picking the offense up and being able to kind of get in there right away and do pretty good. And sometimes it can be a little bit different taking snaps from [different] centers. I know I loved taking the snap from Matt because I could basically stand straight up because he was so high.

"I was a little bit worried about Gino at first, because I didn’t think he was going to be like that, but he’s been great. I’ve been comfortable underneath of him, and like I said, he’s a bright guy. He’s picked the offense up quickly and he’s making all of his calls quickly and getting our offense going and allowing us to set that tempo.”

For veteran offensive tackle Bryant McKinnie, this will mark an unfamiliar time since he had played with Birk going back to their days with the Minnesota Vikings.

“Matt has been there probably my whole career, except for like a year or two," McKinnie said. "I’m kind of familiar with Gino, and I’m getting to know AQ. I have a lot of confidence in Gino. Gino was here last year. He knows the system. He’s out there fighting and grinding with us, so pretty good.”

Gradkowski gets high marks for his athleticism and his performance in the regular-season finale against a Cincinnati Bengals defensive line headlined by Pro Bowl defensive tackle Geno Atkins. But at 6 feet 3, 300 pounds, he is slightly undersized.

"I think people probably look at Gino and think, 'Oh, he's kind of a small guy,'" Ravens assistant general manager Eric DeCosta said during The Baltimore Sun Sports Forum. "He's a small-school guy and he's probably not the biggest guy physically, but I think he's a gritty, smart, tough guy, very quick-footed. He fits our zone blocking scheme very well.

"He's definitely going to have every opportunity to be a starting center for us this year. He's going to have some competition. He's got the right mentality, the right makeup, the drive to be a good player. He comes from a football family. He's an important piece of the puzzle."

Gradkowski spent his rookie season soaking up knowledge from Birk: learning how to snap the football precisely to quarterback Joe Flacco, how to diagnose defenses' blitz and stunt packages to make line calls, and acquiring the work habits of a professional offensive lineman.

"I don't think I could ever replace a guy like Matt, especially off the field, with his leadership qualities in the locker room," Gradkowski told The Sun earlier this year. "He's unlike any other person I've ever been around. I'm just excited for the opportunity. I know I'll have to earn this spot because nothing is ever just handed to you."

Gradkowski's most extensive action was against the Bengals, where he was in for 73 of 89 offensive snaps.

"Gino will be fine," Birk said during his retirement announcement in February. "The one thing about football is there's a lot of tangible things or requirements that you need, but I think the biggest thing about football is that it's a character game, because it's hard.

"It's different from other sports, and Gino's got that. He's a great guy. He's got a fantastic family, and Gino will do whatever it takes to be successful."